Ahammad Z S, Sreekrishnan T R, Hands C L, Knapp C W, Graham D W
School of Civil Engineering & Geosciences, Newcastle University , Newcastle upon Tyne, United Kingdom.
Environ Sci Technol. 2014;48(5):3014-20. doi: 10.1021/es405348h. Epub 2014 Feb 21.
Antibiotic resistance (AR) is often rooted in inappropriate antibiotic use, but poor water quality and inadequate sanitation exacerbate the problem, especially in emerging countries. An example is increasing multi-AR due to mobile carbapenemases, such as NDM-1 protein (coded by blaNDM-1 genes), which can produce extreme drug-resistant phenotypes. In 2010, NDM-1 positive isolates and blaNDM-1 genes were detected in surface waters across Delhi and have since been detected across the urban world. However, little is known about blaNDM-1 levels in more pristine locations, such as the headwaters of the Upper Ganges River. This area is of particular interest because it receives massive numbers of visitors during seasonal pilgrimages in May/June, including visitors from urban India. Here we quantified blaNDM-1 abundances, other AR genes (ARG), and coliform bacteria in sediments and water column samples from seven sites in the Rishikesh-Haridwar region of the Upper Ganges and five sites on the Yamuna River in Delhi to contrast blaNDM-1 levels and water quality conditions between season and region. Water quality in the Yamuna was very poor (e.g., anoxia at all sites), and blaNDM-1 abundances were high across sites in water (5.4 ± 0.4 log(blaNDM-1·mL(-1)); 95% confidence interval) and sediment (6.3 ± 0.7 log(blaNDM-1·mg(-1))) samples from both seasons. In contrast, water column blaNDM-1 abundances were very low across all sites in the Upper Ganges in February (2.1 ± 0.6 log(blaNDM-1·mL(-1))), and water quality was good (e.g., near saturation oxygen). However, per capita blaNDM-1 levels were 20 times greater in June in the Ganges water column relative to February, and blaNDM-1 levels significantly correlated with fecal coliform levels (r = 0.61; p = 0.007). Given that waste management infrastructure is limited in Rishikesh-Haridwar, data imply blaNDM-1 levels are higher in visitor's wastes than local residents, which results in seasonally higher blaNDM-1 levels in the river. Pilgrimage areas without adequate waste treatment are possible "hot spots" for AR transmission, and waste treatment must be improved to reduce broader AR dissemination via exposed returning visitors.
抗生素耐药性（AR）往往源于抗生素的不当使用，但水质差和卫生设施不足加剧了这一问题，尤其是在新兴国家。一个例子是由移动碳青霉烯酶导致的多重耐药性增加，比如NDM-1蛋白（由blaNDM-1基因编码），它可产生极端耐药表型。2010年，在德里各地的地表水中检测到了NDM-1阳性分离株和blaNDM-1基因，此后在世界各地的城市中均有发现。然而，对于像恒河上游源头这样更原始地区的blaNDM-1水平却知之甚少。该地区特别引人关注，因为在5月/6月的季节性朝圣期间会迎来大量游客，包括来自印度城市的游客。在这里，我们对恒河上游瑞诗凯诗 - 哈里瓦地区7个地点以及德里亚穆纳河5个地点的沉积物和水柱样本中的blaNDM-1丰度、其他抗生素耐药基因（ARG）和大肠菌群进行了量化，以对比季节和地区之间的blaNDM-1水平及水质状况。亚穆纳河的水质非常差（例如，所有地点均缺氧），两个季节的水样（5.4 ± 0.4 log(blaNDM-1·mL(-1))；95%置信区间）和沉积物样本（6.3 ± 0.7 log(blaNDM-1·mg(-1))）中blaNDM-1丰度都很高。相比之下，2月恒河上游所有地点的水柱中blaNDM-1丰度非常低（2.1 ± 0.6 log(blaNDM-1·mL(-1))）且水质良好（例如，氧气接近饱和）。然而，恒河水柱中6月的人均blaNDM-1水平相对于2月高出20倍，且blaNDM-1水平与粪大肠菌群水平显著相关（r = 0.61；p = 0.007）。鉴于瑞诗凯诗 - 哈里瓦的废物管理基础设施有限，数据表明游客废物中的blaNDM-1水平高于当地居民，这导致河中blaNDM-1水平在季节上更高。没有适当废物处理的朝圣地区可能是抗生素耐药性传播的“热点”，必须改善废物处理以减少通过返程暴露游客造成的更广泛的抗生素耐药性传播。
